I know this might not be possible due to the fact that a sci-fi version of RMU will be at least a couple (if not more) years out, but it might be worth considering combining such a work into covering the Imperium setting for all the rule systems: HARP-SF, SM2/C, SM-P, and SMU.
I had thought about offering to try my hand at something like this, but have little enough spare time as it is with my current writing project and other things going on.